disconnecting my battery?

Question

if i have a 97 model car with an ecu computer, is there anything i need to know before disconnecting the battery?

Answer 1

Is there any mechanics that will laugh with me when you see some one post an answer say ing that if you disconnect the positive and let the cable touch earth it will spark?
Once you have disconnected it there is no power going through it, there fore how can it spark?
Listen to some one that knows what they are talking about.
remove your key from the ignition so the ECU powers down.
Disconnect the negative terminal first, then the positive.
When refitting the battery, reconnect the positive first then the negative.
If you have a radio that has an active memory, you can buy a device that plugs into your cigarette lighter socket that will stop memory loss there fore meaning you will not have to worry about the radio code, if not then make sure you know the code before you disconnect the battery.
all the settings in the computer are put there by the manufacturer and no matter how long you have the battery disconnected they will not be lost, also is the car runs rough after you reconnect the battery then something has spiked the system prior to your battary failure and the ECU will have to be replaced.
The only thing that will have to be reset is if your cars transmission has an active learning feature, but this can be reset by driving the car normaly for about 5kms or 3 miles.
Other than that, no problems.

Answer 2

Disconnecting the battery won't affect your ECU, the "settings" are saved into a chip which won't change anything. What you need to worry about are memory settings for say power seats and the radio that will be gone once the battery is disconnected. If your battery has "theft feature" where you need to enter a code, you'll need this code once the battery is reconnected or you get NO RADIO.

Short of this, nothing to worry about.

Agree with above DISCONNECT NEGATIVE (BLACK) FIRST. If you disconnect the positive (red) and just lay it on something (metal) you'll have a nice SPARK and probably burnt fingers too...

Answer 3

Black(negative) First. Than the Red(positive). I would disconnect both to decrease the chance of having an accidental connection. When the cables sit in the same place for a while normally when you disconnect them they will try to move back to the place you just took them away from creating an accidental connection. Disconnect both and try to tuck them away from the battery, or cover them up with something.

Answer 4

Some of these guys don't know what they are talking about. Disconnect your negative first. If your negative is still connected and your positive accidentally touches something, it will short and cause sparks and heat. If your negative touches something when your positive cable is attached, it will just ground and nothing will happen. Other than that, just make sure you know how to reset the clock on your stereo because it will reset along with anything else you have like a built in garage door opener or memory seat settings.

Answer 5

You shouldn't run into any problems disconnecting the battery, as long as you don't keep it disconnected for a long period of time.

The computer has a keep alive memory in it and if the car loses power for so long it will drain the keep alive memory and you will have to have the computer reprogramed.
Hope this helps!

Answer 6

No problem. Your engine may run a little rough for a few minutes until the ECU resets itself when you reconnect the battery and start your engine.

Answer 7

The computer and radio will lose it's memory (some radios will lock up if they have an anti-theft feature)and have to be reset---parts stores or JC Whitney sell a device that plugs into your cigarette lighter and attaches to a 9 volt battery that prevents the computer and radio from losing their memory while the battery is disconnected for a short time. Or you can hook up a 9 volt battery to your regular battery cable connections terminal block and ground with jumper wires to get the same results.
http://www.jcwhitney.com/webapp/wcs/stores/servlet/Product?storeId=10101&Pr=p_Product.CATENTRY_ID%3A2008097&TID=101&productId=2008097&catalogId=10101
http://www.amazon.com/CTA-Tools-Computer-Memory-Saver/dp/B000GKD5Q0
http://www.harborfreight.com/manuals/93000-93999/93550.pdf

Answer 8

Nope. It will not harm your computer to disconnect the battery. It will reset your clock, but that's about it.

Answer 9

No the computer should reset itself

Answer 10

not nessesarily, just disconnect the positive first then the negative.